This invention relates generally to combustion devices and, more particularly, to emission control systems for combustion devices.
During a typical combustion process within a furnace or boiler, for example, a flow of combustion gas is produced. The combustion gas contains combustion products including, without limitation, carbon dioxide, carbon monoxide, water, hydrogen, nitrogen and mercury generated as a direct result of combusting solid and/or liquid fuels. Before the combustion gas is emitted into the atmosphere, hazardous or toxic combustion products, such as mercury emissions and oxides of nitrogen (NOx), are to be removed according to EPA or state governmental regulations, standards and procedures.
At least some conventional methods of removing mercury from combustion gases include injecting activated carbon into the combustion gas as the combustion gases flow through duct work. However, with such methods, it may be difficult to obtain uniform distribution of the particulate matter within the duct work. As a result of poor mixing and/or carbon fallout, mercury may not be efficiently removed from the combustion gases. In an attempt to solve such problems, an injection rate of activated carbon is increased, which may further exacerbate the problems associated with the conventional methods.